PURPOSE: We examined the population demographics and club drugs used in gay circuit parties and estimated the reported unsafe sexual behavior associated with each drug, the reasons for attending circuit parties, and the unsafe sex associated with different reasons.

METHODS: A brief questionnaire was provided to a nonrandom sample of party attendees covering demographics, drugs used, sexual activity, and reasons for attending gay circuit parties at three major North American parties in 1998-1999. A total of 1169 usable questionnaires were obtained. Odds ratios for unsafe sex for the drugs surveyed [alcohol, marijuana, methylenedioxymethamphetamine (Ecstasy), ketamine (Special K), crystal methamphetamine (crystal meth), cocaine, volatile nitrites (poppers), and gamma-hydroxybutyrate (GHB)] were calculated, as was significance of unsafe sex for the 10 major reasons for attending parties.

RESULTS: 12-month party drug use was high: > 50% reported using alcohol, Ecstasy, and Special K. Frequent (rather than occasional) use of Ecstasy, Special K, and poppers had an association with unsafe sex at parties. Poppers also showed a statistically significant association with unsafe sex in 12 months (not necessarily at parties) while crystal meth and GHB showed a trend. Attending circuit parties 'to look and feel good,' 'to have sex,' and 'to be uninhibited and wild' were associated with higher levels of unsafe sex in 12 months. IMPLICATIONS: In this sample, circuit party attendees are well educated and financially secure. Party drug use is high. It appears that use of poppers, Ecstasy, Special K, crystal meth, and GHB are associated with various measures of unsafe sex. More comprehensive research on club drug use in gay men is required.